1. Field of the Invention
This invention relates to a zoom lens device of a type, in which, by interchanging the zooming section alone with a fixed part (or relay section) remaining as it is, the same result is obtained as in the case of interchanging the lens system as a whole.
2. Description of the Prior Art
In a picture-taking apparatus or the like, when it is desired to carry out photographic operations by interchanging lenses having different magnification, etc., there are three known methods, namely, a first one is to interchange the entire lens system, a second one is to connect a separate lens, for example, an afocal converter lens to the existing lens system, and a third one is to interchange only a part of the lens system with another lens.
The lens device of the present invention pertains to the third method mentioned above. However, this third method has heretofore been adopted for interchange of monofocal lenses, and not for the interchange of zoom lenses. The reason is that since zoom lenses have been designed primarily to minimize variations in aberration to occur in the zooming section during the zooming operation, and secondly to correct, at the relay section, the aberration occurring in the zooming section, it has been regarded as impossible to assemble another zooming section to the relay section.
On the other hand, in the field of TV cameras, miniaturization of the optical system has been desired as in the case of emergence of handy or compact camera.